Richard played Lee Preston in the fifth and last series of Cold Feet broadcast in 2003. He appeared in all four episodes of the comedy-drama series as the swimming instructor who has a relationship with Karen's nanny Ramona.

The series was due to end after four series in 2001, but writer Mike Bullen was eventually persuaded to write a final series of just four episodes. The final episode was watched by more viewers than any previous episode, a total of 10.7 million. Numerous accolades were given to the series, particularly for the final episode, including the prestigious Best Comedy Award at the British Comedy Awards.

According to this interview with the Sunday Mirror in August 2002, Richard Armitage secured the role of Lee when he arrived at his audition wearing a pair of old boots, which impressed the producer. He worked out to match the scripted description of his character and took aqua-aerobics lessons to understand Lee's profession. His first scene was a kissing scene with Ramona, and the actress sprayed breath freshener into his ear as a joke just before the cameras rolled.

Episode One

Three months after marrying in Australia, Pete and Jo return to the UK only to find Pete's mum Audrey asking to live with them. Adam and Rachel have a new baby boy though soon suffer the stresses of being new parents. Rachel spends more time with her son than with Adam who feels neglected and he walks out on his son's naming ceremony.

Karen and David file for divorce though try to settle it amicably. Ramona meets swimming instructor Lee at a health club.

Episode Two

Rachel returns to work and Adam is left with the baby as he is made redundant, but eventually gets a new job while Rachel is away. Pete and Jo are interviewed by immigration who suspect the marriage isn't legitimate. The marriage is in trouble when Pete finds an email from her which casts doubts on her affections for him.

David sleeps with his lawyer, Robyn, who wants him to seek custody of his children, while Karen asks a reluctant Mark (Sean Pertwee) to spend more time with her children. Ramona and Lee spend the night together.

Episode Three

Pete and Jo resolve to mend their marriage, but when Jo goes away on a trip she sleeps with Lee (Richard Armitage), despite the fact that Lee has asked Ramona to move in with him. Jo later confesses the affair to Karen.

David avoids contact with Robyn as it was affecting the divorce petition but then they make up and he decides to introduce her to his friends.

Adam and Rachel have to look for a new home when Adam's landlord dies and the house is put up for auction. His father, Bill, turns up and after a difficult reunion Adam tries to bond with him. Bill puts up the extra money needed so that Adam can bid for his home, and he wins it. He calls Rachel to tell her, but she is driving and when she hangs up she has a car crash. Her friends gather at her hospital bedside but she dies.

Episode Four

The group gather for Rachel's funeral as Jenny (Fay Ripley) returns, heavily pregnant, to the last ever episode of the series. Adam keeps seeing Rachel everywhere and he returns to work almost immediately rather than dealing with his grief.

Lee asks Ramona to marry him which results in Karen telling Ramona that Lee had an affair with Jo and Pete also discovers the infidelity. Jo invites Jenny to stay with her and Pete and as a result Pete and Jenny grow closer. David has to choose between Robyn and Karen.

The group travels to Portmeirion to scatter Rachel's ashes. When they return Pete asks Jo for a divorce and she decides to return to Australia. Jenny moves in with Pete. David resumes his relationship with Robyn and Karen and Ramona plan a holiday in Spain. Adam calls his father and packs his belongings, leaving Manchester with his son Matthew.